Oxypropylated fractional esters of polycarboxylic acids



Patentecl Sept. 15, 19 53 OXYPROPYLATED FRACTIONAL ESTERS OFPOLYCARBOXYLIC ACIDS Melvin De Groote, University City, Mo., assignor toPetrolite Corporation, a corporation of Delaware No Drawing. ApplicationMay 14, 1951, Serial No. 226,333

7 Claims.

The present invention is concerned with certain new chemical products,compounds, or compositions which have useful application in variousarts. It includes methods or procedures for manufacturing said newchemical products, compounds, or compositions, as well as the products,compounds, or compositions themselves.

Said new compositions are fractional esters obtained from a polycarboxyacid and a diol obtained by the oxypropylation of a primary alicyclicamine having not more than 7 carbon atoms and containing a cyclohexylradical. For all practical purposes, this limits the amine to productsobtained by the hydrogenation of aniline, benzylarnine, and a toluidine,such as orthotoluidine. Such compounds are cyclohexylamine,methylcyclohexylamine, and cyclohexylmethylamine. Furthermore, thedihydroxylated compound, prior to esterification, must be waterinsolubleand kerosene-soluble. Momentarily, ignoring certain variants ofstructure, which will be considered subsequently, the compounds may beexemplified by the followin formula:

in which R is the cyclohexyl radical, the methylcyclohexyl radical, orthe cyclohexylmethyl radical, and n and n are whole numbers with theproviso that n plus 11. equals a sum varying from to 80; n is a wholenumber not over 2, and R is the radical of the polycarboxy acid.

coon

ooonw and preferably free from any radical having more than 8uninterrupted carbon atoms in a single group, and with the furtherproviso that the parent dihydroxy compound, prior to esterification, bewater-insoluble and kerosene-soluble.

Attention is directed to the co-pending application of Charles M. Blair,Jr., Serial No. 70,811, filed January 13, 1949 (now Patent 2,562,878,granted August 7, 1951), in which there is described, among otherthings, a process for breaking petroleum emulsions of the water-in-oiltype characterized by subjecting the emulsion to the action of anesterification product of a dicarboxylic acid and a polyalkylene glycol,in which the ratio of equivalents of polybasic acid to equivalents ofpolyalkylene glycol is in the ran e of 0.5 to 2.0, in which the alkylenegroup has from 2 2 to 3 carbon atoms, and in which the molecular weightof the product is between 1,500 to 4.000.

Similarly, there have been used esters of dicarboxy acids andpolypropylene glycols, in which 2 moles of the dicarboxy acid ester havebeen reacted with one mole of a polypropylene glycol having a molecularweight, for example, of 2,000 so as to form an acidic fractional ester.Subsequent examination of what is said herein, in comparison with theprevious example as well as the hereto appended claims, will show theline of delineation between such somewhat comparable compounds. Ofgreater significance, however, is what is said subsequently in regard tothe structure of the parent diol, as compared to polypropylene glycolswhose molecular weights may vary from 1,000 to 2,000.

The cheapest of the three amines which can be employed iscyclohexylamine and this is my preferred reagent.

Although the herein described products have a number of industrialapplications, they are of particular value for resolving petroleumemulsions of the water-in-oil type, that are commonly referred to as cutoil, roily oil, emulsified oil, etc., and which comprise fine dropletsof naturally-occurring waters or brines dispersed in a more or lesspermanent state throughout the oil which constitutes the continuousphase of the emulsion. This specific application is described andclaimed in my co-pending application Serial No. 226,332, filed May 14,1951.

The new products are useful as wetting, deterent and leveling agents inthe laundry, textile and dyeing industries; as wetting agents anddetergents in the acid washing of building stone and brick; as wettingagents and spreaders in the application of asphalt in road building andthe like; as a flotation reagent in the flotation separation of variousaqueous suspensions containing negatively charged particles, such assewage, coal washing waste water, and various trade wastes and the like;as germicides, insecticides, emulsifying agents, as, for example, forcosmetics, spray oils, water-repellent textile finishes; as lubricants,etc.

For convenience, what is said hereinafter will be divided into fourparts:

Part 1 is concerned with the preparation of the oxypropylationderivatives of the specified amines;

Part 2 is concerned with the preparation of the esters from theoxypropylated derivatives;

Part 3 is concerned with the structure of the oxypropylation productsobtained from the specisure during reaction, etc.

fied alicyclic amines. Insofar that such materials are dihydroxylated,there is a relationship to ordinary diols which do not contain anitrogen atom, all of which is considered briefly in this particularpart; and

Part 4 is concerned with certain derivatives which can be obtained fromthe oxypropylated primary amines. In some instances, such derivativesare obtained by modest oxyethylation preceding the oxypropylation step,or oxypropylation followed by oxyethylation. This results in diolshaving somewhat different properties which can then be reacted with thesame polycarboxy acids or anhydrides described in Part 3 to giveeffective demulsifying agents. For this reason, a description of theapparatus makes casual mention of oxyethylation. For the same reasonthere is brief mention of the use of glycide.

PART 1 For a number of well known reasons equipment, whether laboratorysize, semi-pilot plant size, pilot plant size, or large scale size, isnot, as a rule, designed for a particular alkylene oxide. Invariably andinevitably, however, or particularly in the case of laboratory equipmentand pilot lant size, the design is such as to use any of the customarilyavailable alkylene oxides, i. e., ethylene oxide, propylene oxide,butylene oxide, glycide, epichlorohydrin, styrene oxide, etc. In thesubsequent description of the equipment it becomes obvious that it isadapted for oxyethylation as well as oxypropylation.

Oxypropylations are conducted under a wide variety of conditions, notonly in regard to pres ence or absence of catalyst, and the kind ofcatalyst, but also in regard to the time of reaction, temperature ofreaction, speed of reaction, pres- For instance, oxyalkylations can beconducted at temperatures up to approximately 200 C. with pressures inabout the same range up to about 200 pounds per square inch. They can beconducted also at temperatures approximating the boiling point of water,or slightly above, as, for example, 95 to 120 C. Under suchcircumstances, the pressure will be less than pounds per square inch,unless some special procedure is employed, as is sometimes the case, towit, keeping an atmosphere of inert gas such as nitrogen in the vesselduring the reaction. Such low-temperature-lowreaction-rateoxypropylations have been described very completely in U. S. Patent No.2,448,664, to H. R. Fife et al., dated September '7, 1948.Low-temperature-lowpressure-oxypropylations are particularly desirablewhere the compound being subjected to oxypropylation contains one, twoor three points of reaction only, such as monohydric alcohols, glycolsand triols.

Although the word glycol or diol is usually applied to compoundscontaining carbon, hydrogen, and oxygen only, yet the nitrogencontainingcompounds herein are diols in the sense that they are dihydroxylated.Thus, the conditions which apply to the oxypropylation of certainglycols also apply in this instance.

Since low-pressure-low-temperature-low-reaction speed oxypropylationsrequire considerable time, for instance, 1 to '7 days of 24 hours eachto complete the reaction, they are conducted, as a rule, whether on alaboratory scale, pilot plant scale, or large scale, so as to operateautomatically. The prior figure of seven days applies especially tolarge-scale operations. I have used conventional equipment with twoadded automatic features:

(a) A solenoid-controlled valve which shuts off the propylene oxide inevent that the temperature gets outside a predetermined and set range,for instance, to 0.; and

(2)) Another solenoid valve which shuts oif the propylene oxide (or forthat matter ethylene oxide if it is being used) if the pressure getsbeyond a predetermined range, such as 25 to 35 pounds. Otherwise, theequipment is substantially the same as is commonly employed for thispurpose, where the pressure of reaction is higher, speed of reaction ishigher, and time of reaction is much shorter. In such instances suchautomatic controls are not necessarily used.

Thus, in preparing the various examples I have found it particularlyadvantageous to use laboratory equipment or pilot plant equipment whichis designed to permit continuous oxyalkylations, whether it beoxypropylation or oxyethylation. With certain obvious changes, theequipment can be used also to permit oxyalkylation involving the use ofglycide, where no pressure is involved except the vapor pressure of asolvent, if any, which may have been used as a diluent.

As previously pointed out, the method of using propylene oxide is thesame as ethylene oxide. This point is emphasized only for the reasonthat the apparatus is so designed and constructed as to use eitheroxide.

The oxypropylation procedure employed in the preparation of theoxyalkylated derivatives has been uniformly the same, particularly inlight of the fact that a continuous, automatically-controlled procedurewas employed. In this procedure the autoclave was a conventionalautoclave made of stainless steel and having a capacity of approximately15 gallons and a working pressure of one thousand pounds gauge pressure.This pressure obviously is far beyond any requirement as far aspropylene oxide goes, unless there is a reaction of explosive violenceinvolved due to accident. The autoclave was equipped with theconventional devices and openings, such as the variable-speed stirreroperating at speeds from 50 R. P. M. to 500 R. P. M.; thermometer welland thermocouple for mechanical thermometer; emptying outlet; pressuregauge, manual vent line; charge hole for initial reactants; at least oneconnection for introducing the alkylene oxide, such as propylene oxideor ethylene oxide, to the bottom of the autoclave; along with suitabledevices for both cooling and heating the autoclave, such as a coolingjacket, and preferably, coils in addition thereto, with the jacket soarranged that it is suitable for heating with steam or cooling withwater, and further equipped with electrical heating devices. Suchautoclaves are, of course, in essence, small-scale replicas of the usualconventional autoclave used in oxyalkylation procedures. In someinstances in exploratory preparations an autoclave having a smallercapacity, for instance, approximately 3 liters in one case and about 1gallons in another case, was used.

Continuous operation, or substantially continuous operation, wasachieved by the use of a separate container to hold the alkylene oxidebeing employed, particularly propylene oxide. In conjunction with thesmaller autoclaves, the container consists essentially of a laboratorybomb having a capacity of about one-half gallon, or somewhat in excessthereof. In some instances, a larger bomb was used, to wit, one having acapacity of about one gallon. This bomb was equipped, also with an inletfor charging, and an eductor tube going to the bottom of the containerso as to permit discharging of alkylene oxide in the liquid phase to theautoclave. A bomb having a capacity of about 60 pounds was used inconnection with the 15-gallon autoclave. Other conventional equipmentconsists, of course, of the rupture disc, pressure gauge, sight feedglass, thermometer, connection for nitrogen for pressuring bomb, etc.The bomb was placed on a scale during use. The connections between thebomb and the autoclave were flexible stainless steel hose or tubing sothat continuous weighings could be made without breaking or making anyconnections. This applies also to the nitrogen line, which was used topressure the bomb reservoir. To the extent that it was required, anyother usual conventional procedure or addition which provided greatersafety was used, of course, such as safety glass protective screens,etc.

Attention is directed again to what has been said previously in regardto automatic controls which shut off the propylene oxide in eventtemperature of reaction passes out of the predetermined range, or ifpressure in the autoclave passes out of predetermined range.

With this particular arrangement practically all oxypropylations becomeuniform, in that the reaction temperature was held within a few degreesof any selected point, for instance, if 105 C. was selected as theoperating temperature the maximum point would be at the most 110 C. or112 C., and the lower point would be 95, or possibly, 98 0. Similarly,the pressure was held at approximately 30 pounds maximum within a5-pound variation one way or the other, but might drop to practicallyzero, especially where no solvent such as xylene is employed. The speedof reaction was comparatively slow under such conditions as comparedwith oxyalkylations at 200 C. Numerous reactions were conducted in whichthe time varied from one day (24 hours) up to three days (72 hours), forcompletion of the final member of a series. In some instances, thereaction may take place in considerably less time, i. e., 24 hours orless, as far as a partial oxypropylation is concerned. The minimum timerecorded was about a 3-hour period in a single step. Reactions indicatedas being complete in hours may have been complete in a lesser period oftime, in light of the automatic equipment employed. This applies alsowhere the reactions were complete in a shorter period of time, forinstance, 4 to 5 hours. In the addition of propylene oxide, in theautoclave equipment as far as possible the valves were set so all thepropylene oxide, if fed continuously, would be added at a rate so thatthe predetermined amount would react within the first hours of the24-hour period or two-thirds of any shorter period. This meant that ifthe reaction was interrupted automatically for a period of time forpressure to drop or temperature to drop the predetermined amount ofoxide, would still be added, in most instances, well within thepredetermined time period. Sometimes where the addition was acomparatively small amount in a 10-hour period, there would be anunquestionable speeding up of the reaction, by simply repeating theexamples and using 3, 4, or 5 hours, instead of 10 hours.

When operating at a comparatively high temperature, for instance,between 150 to 200 C.,

an unreacted alkylene oxide such as propylene oxide, makes its presencefelt in the increase in pressure, or the consistency of a higherpressure. However, at a. low enough temperature it may happen that thepropylene oxide goes in as a liquid. If so, and if it remains unreacted,there is, of course, an inherent danger and appropriate steps must betaken to safeguard against this possibility; if need be, a sample mustbe withdrawn and examined for unreacted propylene oxide. One obviousprocedure, of course, is to oxypropylate at a modestly highertemperature, for instance, at 140 to 150 C. Unreacted oxide afiectsdetermination of the acetyl or hydroxyl value of the hydroxylatedcompound obtained.

The higher the molecular weight of the compound, i. e., towards thelatter stages of reaction, the longer the time required to add a givenamount of oxide. One possible explanation is that the molecule, beinglarger, the opportunity for random reaction is decreased. Inversely, thelower the molecular weight, the faster the reaction takes place. Forthis reason, sometimes at least, increasing the concentration of thecatalyst does not appreciably speed up the reaction, particularly whenthe product subjected to oxyalkylation has a comparatively highmolecular weight. However, as has been pointed out previously, operatingat a low pressure and a low temperature, even in large scale operations,as much as a week or ten days time may lapse to obtain some of thehigher molecular weight derivatives from monohydric or dihydricmaterials.

In a number of operations the counterbalance scale or dial scale holdingthe propylene oxide bomb was so set that when the predetermined amountof propylene oxide had passed into the reaction, the scale movementthrough a time operating device was set for either one to two hours, sothat reaction continued :for 1 to 3 hours after the final addition ofthe last propylene oxide and thereafter the operation was shut down.This particular device is particularly suitable for use on largerequipment than laboratory size autoclaves, to wit, on semi-pilot plantor pilot plant size, as well as on large scale size. This final stirringperiod is intended to avoid the presence of unreacted oxide.

In this sort of operation, of course, the temperature range wascontrolled automatically by either use of cooling water, steam, orelectrical heat, so as to raise or lower the temperature. The pressuringof the propylene oxide into the reaction vessel was also automatic,insofar that the feed stream was set for a slow, continuous run whichwas shut off in case the pressure passed a predetermined point, aspreviously set out. All the points of design, construction, etc., wereconventional, including the gauges, check valves and entire equipment.As far as I am aware, at least two firms, and possibly three, specializein autoclave equipment, such as I have employed in the laboratory, andare prepared to furnish equipment of this same kind. Similarly, pilotplant equipment is available. This point is simply made as a precautionin the direction of safety. Oxyalkylations, particularly involvingethylene oxide, glycide, propylene oxide, etc., should not be conductedexcept in equipment specifically designed for the purpose.

Example 1a Of the various alicyclic compounds previously enumerated, theone which is most readily available commercially is cyclohexylamine.Although the other alicyclic amines would be equally satisfactory andreact in the same manner, I have preferred to use cyclohexylamine forpurpose of illustration, because of its ready availability.

The starting material was a commercial grade of cyclohexylamine as soldby Monsanto Chemical Company, St. Louis, Missouri. The particularautoclave employed was one with a capacity of gallons, or on the averageof about 120 pounds of reaction mass. The speed of the stirrer could bevaried from 150 to 350 R. P. M. 15.25 pounds of cyclohexylamine werecharged into the autoclave along with 1 pounds of caustic soda. Thereaction pot was flushed out with nitrogen; the autoclave sealed, andthe automatic devices adjusted for injecting a total of 79 pounds ofpropylene oxide in approximately a five-hour period. The regulator wasset for a maximum pressure of 37 pounds per square inch. This meant thatthe bulk of the reaction could take place, and probably did take place,at a lower pressure. This comparatively lower pressure was the result ofthe fact that considerable catalyst was present, especially when oneallows for the fact that the cyclohexylamine as such has some basicityof its own. The addition of propylene oxide was fairly slow, forinstance, about pounds per hour. The addition was made at a temperatureof 22D-225 R, that is, somewhat moderately above the boiling point ofwater. The initial introduction of propylene oxide was not made untilthe heating devices had raised the temperature somewhat above theboiling point of water, for instance, about 217 or 218 F., that is,slightly higher than 100 C. At the completion of the reaction, a samplewas taken and oxypropylation proceeded as in Example 2a, immediatelyfollowing.

Example 2a 61.1 pounds of the reaction mass identified as Example la,preceding, and equivalent to 9.75 pounds of the amine, 50.4 pounds ofpropylene oxide, and .95 pound of caustic soda, were allowed to remainin the reaction vessel and without adding any more catalyst subjected toreaction with 11.75 pounds of propylene oxide. The oxypropylation wasconducted in substantially the same manner with regard to temperatureand pressure, as in Example 10., preceding, except that the reactiontime was short, 1. e., 3 hours. The oxide was added at about the rate of5 pounds per hour. At the end of the reaction period, part of the samplewas withdrawn and oxypropylation was continued as described in Example3a, following.

Example 3a 65.1 pounds of the reaction mass identified as Example 2a,preceding, and equivalent to 8.71 pounds of cyclohexylamine, 55.54pounds of propylene oxide, and .85 pound of caustic soda, were permittedto remain in the reaction vessel. 25 pounds of propylene oxide wereintroduced in this third stage. No additional catalyst was added. Thetime required was the same as in the preceding period, 1. e., 3 hours.The addition was at the rate of about 10 pounds per hour. The conditionsof reaction, as far as temperature and pressure were concerned, weresubstantially the same as in Example 1a, preceding. At the completion ofthe reaction, part of the reaction mass was withdrawn and the remaindersubjected to oxypropylation, as described in Example 4a, immediatelyfollowing.

Example 4a 61.72 pounds of the reaction mass identified as Example 3a,preceding, and equivalent to 5.96 pounds of cyclohexylamine, 55.18pounds of propylene oxide, and .58 pound of caustic soda were permittedto remain in the autoclave. Without adding any more catalyst this wassubjected to further oxypropylation in the same manner as in precedingexamples. The amount of propylene oxide added was 43 pounds. This wasadded in a 3-hour period at a rate of about 17 to 18 pounds per hour.Conditions in regard to temperature and pressure were substantially thesame as in Example 1a, preceding. At the end of the reaction period partof the sample was withdrawn and the remainder of the reaction mass wassubjected to further oxypropylation, as described in Example 5a,following.

Example 5a 67.2 pounds of the reaction mass identified as Example 4a,preceding, were permitted to remain in the autoclave. This wasequivalent to 3.9 pounds of cyclohexylamine, 62.95 pounds of propyleneoxide, and .37 pound of caustic soda. 37.25 pounds of propylene oxidewere added. The time required to add this propylene oxide wasconsiderably longer than previously, to wit, 8 hours. This was due, inpart, to the lower concentration of catalyst. The oxide was added at therate of about 6 pounds per hour. The conditions of reaction in regard totemperature and pressure were substantially the same as in Example la,preceding. Part of the reaction mass was withdrawn and the remaindersubjected to further oxypropylation, as described in Example 6a,immediately following.

Example 6a 67.8 pounds of reaction mass identified as Example 5a,preceding, and equivalent to 2.53 pounds of cyclohexylamine, 65.03pounds of propylene oxide, and .24 pound of caustic soda were subjectedto further oxypropylation. No additional catalyst was introduced. 32.5pounds of propylene oxide were added. The addition was made under thesame conditions as in Example 5a, preceding, 1. e., 8 hours for additionof the oxide, with temperature and pressure the same as in Example 1a,preceding; and also, for that matter, the same as in Example 5a,preceding. The oxide was added at a rate of about 5 pounds per hour.When the reaction was complete, part of the mass was withdrawn and theremainder subjected to further oxypropylation, as described in Example7a, immediately following.

Example 7a 64.55 pounds of reaction mass equivalent to 1.67 pounds ofcyclohexylamine, 62.73 pounds of propylene oxide, and .15 pound ofcaustic soda, were subjected to further oxypropylation without theaddition of any catalyst. The amount of oxide added was 12.5 pounds; theaddition rate was rather slow, being at the rate of 4 pounds per hour.The oxypropylation was complete in 4 hours. The conditions oftemperature and pressure were the same as in Example 1a, preceding.

Ewample 8a 55.68 pounds of reaction mass identified as Example 7a,preceding, equivalent to 1.21 pounds of cyclohexylamine, 54.36 pounds ofpropylene oxide, and .11 pound of caustic soda, were subjected tofurther oxypropylation without the addition of any catalyst. The amountof oxide added was 39.25 pounds. Due to the low concentration ofcatalyst, the addition was rather slow, at the rate of about 4 /2 poundsper hour. The time required to add the oxide was 10 hours. Theconditions, as far as temperature and pressure were concerned, were thesame as in Example 1a, preceding.

In this particular series of examples the oxypropylation was stopped atthis stage. In other series I have continued the oxypropylation, so thatthe theoretical molecular weight varied from 9,000 to 10,000, but theincrease in molecular weight by hydroxyl determination was comparativelysmall, for instance, about 150 to 200.

What is said herein is presented in tabular form in Table 1, immediatelyfollowing, with some added information as to molecular weight and as tosolubility of the reaction product in water, xylene and kerosene.

factorily as an index to the molecular weight as any other procedure,subject to the above limitations, and especially in the higher molecularweight range. If any difiiculty is encountered in the manufacture of theesters, as described in Part 2, the stoichiometrical amount of acid oracid compound should be taken which corresponds to the indicated acetylor hydroxyl value. This matter has been discussed in the literature andis a matter of common knowledge and requires no further elaboration. Infact, it is illustrated by some of the examples appearing in the patentpreviously mentioned.

PART 2 As previously pointed out, the present invention is concernedwith acidic esters obtained from the oxypropylated derivatives describedin Part 1, immediately preceding, and polycarboxy acids, particularlytricarboxy acids, like citric and dicarboxy acids such as adipic acid,phthalic acid, or anhydride, succinic acid, diglycollic acid, se-

TABLE I Composition before Composition at end M W lllx No h zi tngx.Time Amine Oxide Cata- Theo. Amine Oxide Oatag 1 lbs. hrs.

amt, amt, lyst, Mol. amt., amt, lyst, min sq. in

lbs. s. lbs. wt. lbs. lbs. lbs.

15. 25 1. 50 G 15. 25 79. 0 1. 50 220-225 35. 37 9. 75 50. 4 95 730 9.75 62. 95 220-225 35. 37 3 8. 71 55. 54 85 1, 015 8. 71 80. 54 85 22022535. 37 3 5. 96 55. 18 58 1, 730 5. 96 98. 18 58 1, 86 220-225 35. 37 33. 90 62. 95 37 2, 640 3. 90 100. 2 37 l, 810 220-225 35. 37 8 2. 53 65.03 24 3, 830 2. 53 95. 28 24 2, 380 220-225 35. 37 8 1. 67 62. 73 l5 4,560 1. 67 75. 23 15 2, 170 220-225 35. 37 4 1, 21 54. 36 ll 7, 770 l. 2193. 01 11 2, 920 220225 35. 37 10 Examples 1a, 2a and 3a wereemulsifiable to bacic acid, azelaic acid, aconitic acid, maleic acidinsoluble in water, and soluble in kerosene and xylene. Examples 4a,through 811, inclusive, were all insoluble in water, but soluble inxylene and kerosene.

Products obtained from hydrogenated benzylamine and hydrogenatedorthotoluidine appear to have approximately the same characteristics asthose derived from cyclohexylamine. The final product, i. e., at the endof the oxypropylation step, was a somewhat viscous liquid with areddish-amber cast. This was characteristic of all the various productsobtained from the three amines. These products were, of course, slightlyalkaline, due to the residual caustic soda and also due to the basicnitrogen atom, which is significant, at least in the case ofbenzylamine. The residual basicity, due to the catalyst, would, ofcourse, be the same if sodium methylate had been used.

Speaking of insolubility in water or solubility in kerosene, suchsolubility test can be made simply by shaking small amounts of thematerials in a test tube with water, for instance, using 1% to 5%approximately based on the amount of water present.

Needless to say, there is no complete conversion of propylene oxide intothe desired hydroxylated compounds. This is indicated by the fact thatthe theoretical molecular weight based on a statistical average isgreater than the molecular weight calculated by usual methods on basisof acetyl or hydroxyl value. Actually, there is no completelysatisfactory method for determining molecular weights of these types ofcompounds with a, high degree of accuracy when the molecular weightsexceed 2,000. In some instances, the acetyl value or hydroxyl valueserves as satisor anhydride, citraconic acid or anhydride, maleic acidor anhydride adducts, as obtained by the Diels-Alder reaction fromproducts such as maleic anhydride, and cyclopentadiene. Such acidsshould be heat-stable so they are not decomposed during esterification.They may contain as many as 36 carbon atoms, as, for example, the acidsobtained by dimerization of unsaturated fatty acids, unsaturatedmonocarboxy fatty acids, or unsaturated monocarboxy acids having 18carbon atoms. Reference to the acid in the hereto appended claimsobviously includes the anhydrides or any other obvious equivalents. Mypreference, however, is to use polycarboxy acids having not over 8carbon atoms.

The production of esters including acid esters (fractional esters) frompolycarboxy acids and glycols or other hydroxylated compounds is wellknown. Needless to say, various compounds may be used such as the lowmolal ester, the anhydride, the acyl chloride, tc. However, for purposeof economy, it is customary to use either the acid or the anhydride. Aconventional procedure is employed. On a laboratory scale one can employa resin pot of the kind described in U. S. Patent No. 2,499,370, datedMarch 7, 1950, to P eGroote & Keiser, and particularly with one moreopening to permit the use of a porous spreader if hydrochloric acid gasis to be used as a catalyst. Such device or absorption spreader consistsof minute alundum thimbles which are connected to a glass tube. One canadd a sulfcnic acid such as paratoluene sulfonic acid as a catalyst.There is some objection to this, because, in some instances, there issome evidence that this acid catalyst tends to decompose or rearrangethe oxypropylated compounds, and particularly likely to do so, if theesterification temperature is too high. In the case of polycarboxy acidssuch as diglycollic acid, which is strongly acidic, there is no need toadd any catalyst. The use of hydrochloric acid gas has one advantageover para-toluene sulfonic acid and that is that at the end of thereaction, it can be removed by flushing out with nitrogen, whereas,there is no reasonably convenient means available of removing thepara-toluene sulfonic acid or other sulfonic acid employed. Ifhydrochloric acid is employed, one need only pass the gas through at anexceedingly slow rate so as to keep the reaction mass acidic. Only atrace of acid need be present. I have employed hydrochloric acid gas orthe aqueous acid itself to eliminate the initial basic material. Mypreference, however, is to use no catalyst whatsoever and to insurecomplete dryness of the diol, as described in the final procedure justpreceding Table 2.

The products obtained in Part 1 preceding may contain a basic catalyst.As a general procedure, I have added an amount of half-concentratedhydrochloric acid considerably in excess of what is required toneutralize the residual catalyst. The mixture is shaken thoroughly andallowed to stand overnight. It is then filtered and refluxed with thexylene present until the water can be separated in a phase-separatingtrap. As soon as the product is substantially free from water thedistillation stops. This preliminary step can be carried out in theflask to be used for esteriflcation. If there is any further depositionof sodium chloride during the reflux stage, needless to say, a secondfiltration may be required. In any event, the neutral or slightly acidicsolution of the oxypropylated derivatives described in Part 1 is thendiluted further with suflicient xylene, decalin, petroleum solvent, orthe like, so that one has obtained approximately a 45% solution. To thissolution there is added a polycarboxylated reactant, as previouslydescribed, such as phthalic anhydride, succinic acid or anhydride,diglycollic acid, etc. The mixture is refluxed until esterification iscomplete, as indicated by elimination of water or drop in carboxylvalue. Needless to say. if one produces a half-ester from an anhydridesuch as phthalic anhydride, no water is eliminated. However, if it isobtained from diglycollic acid, for example, water is eliminated. Allsuch procedures are conventional and have been so thoroughly describedin the literature that further consideration will be limited to a fewexamples and a comprehensive table.

Other procedures for'eliminating the basic residual catalyst, if any,can be employed. For example, th oxyalkylation can be conducted inabsence of a solvent, or the solvent removed after oxypropylation. Suchoxypropylation end product can then be acidified with just enoughconcentrated hydrochloric acid to just neutraliz the residual basiccatalyst. To this product one can then add a small amount of anhydroussodium sulfate (sufficient in quantity to take up any water that ispresent) and then subject the mass to centrifugal force so as toeliminate the hydrated sodium sulfate and probably the sodium chlorideformed. The clear somewhat viscous, reddish amber liquid so obtained maycontain a small amount of sodium sulfate or sodium chloride, but, in anyevent, is perfectly acceptable for esterification in the mannerdescribed.

It is to be pointed out that the products here described are notpolyesters in the sense that there is a plurality of both diol radicalsand acid radicals; the product is characterized by having only one diolradical.

In some instances, and, in fact, in many instances, I have found that,in spite of the dehydration methods employed above, a mere trace ofwater still comes through and that this mere trace of water certainlyinterferes with the acetyl or hydroxyl value determination, at leastwhen a number of conventional procedures are used, and may retardesterification, particularly where there is no sulfonic acid orhydrochloric acid present as a catalyst. Therefore, I have preferred touse the following procedure: I have employed about 200 grams of thediol, as described in Part 1, preceding; I have added about 60 grams ofbenzene, and then refluxed this mixture in the glass resin pot, using aphase-separating trap until the benzene carried out all the waterpresent as water of solution or the equivalent. Ordinarily, thisrefluxing temperature is apt to be in the neighborhood of 130 topossibly 150 C. When all this water or moisture has been removed, I alsowithdraw approximately 20 grams or a little less benzene, and then addthe required amount of the carboxy reactant and also about 150 grams ofa high boiling aromatic petroleum solvent. These solvents are sold byvarious oil refineries, and, as far as solvent effect, act as if theywere almost completely aromatic in character. Typical distillation datain the particular type I have employed and found very satisfactory isthe following:

I. B. P., 142 C. 50 ml., 242 C. 5 ml., 220 C. 55 ml., 244 C. 10 ml., 209C. 60 ml., 248 C, 15 ml., 215 C. 65 ml., 252 C. 20 ml., 216 C. 70 ml.,252 C. 25 ml., 220 C. '75 ml., 260 C. 30 ml., 225 C. 80 ml., 264 C. 35ml., 230 C. 35 ml., 270 C. 40 ml., 234 C. ml., 280 C. 45 ml., 237 C.ml., 307 C,

After this material is added, refluxing is con tinued, and, of course,is at a high temperature, to wit, about to C. If the carboxy reactant isan anhydride, needless to say, no water of reaction appears; if thecarboxy reactant is an acid, water of reaction should appear and shouldbe eliminated at the above reaction temperature. If it is noteliminated, I simply separate out another 10 to 20 cc. of benzene bymeans of the phase-separating trap, and thus raise the temperature to orC., or even to 200 C., if need be. My preference is not to go above 200C.

The use of such solvent is extremely satisfactory, provided one does notattempt to remove the solvent subsequently except by vacuumdistillation, and provide there is no objection to a little residue.Actually, when these materials are used for a purpose such asdemulsification, the solvent might just as well be allowed to remain. Ifthe solvent is to be removed by distillation, and particularly vacuumdistillation, then the high boiling aromatic petroleum solvent mightwell be replaced by some more expensive solvent, such as decalin or analkylated decalin which has a rather definite or close range boilingpoint. The removal of the solvent, of course, is purely a conventionalprocedure and requires no elaboration.

In the appended table, solvent #7-3, which appears in all instances, isa mixture of 7 volumes of the aromatic petroleum solvent, previouslydescribed, and 3 volumes of benzene. This was used, or a similarmixture, in the manner previously described. In a large number ofsimilar examples decalin has been used, but it is my preference to usethe above mentioned 14 sonable speed, either raise the temperatureindicated, or else extend the period of time up to 12 or 16 hours, ifneed be;

(c) If necessary, use of paratoluene sult d 1 1 n th fonic acid, or someother acid as a catalyst; 2 g fi gi g gg i z 5 32 32 22? (d) If theesterification does not produce a p clear product, a check should bemade to see if mtend to remove the solvent, my preference is aninorganic salt Such as sodium choride or to use the petroleum solvent,benzene mixture, Sodium zulfat t t although obviously, any of the othermixtures. 1 e no 3 mg such as decalm and Xylene, can be employed Suchsalt should be el mlnated, at least for The data included in thesubsequent tables, 1. e4131011510011 experlmeniatwn. and can b e.,Tables 2 and 3, are self-explanatory, and very moved y fi l v y ng elsebeing eq complete and it is believed no further elaboration as the sizeof the molecule increases and the reis necessary: active hydroxylradical represents a smaller frac- TABLE 2 Amt. Amt. of Ex. Theo. Theo.Actual wt. Ex. No 0f polycarofacid N0 M W based hyd. Polycarboxyreactant boxy reester of oxy. cfC yl Cof drolxyl can 1 cmpd actant cmpdH. va ue (gm) (gm) 40 1,730 64.7 75.4 1,486 202 Diglycollicacid 36.2 4111,730 64.7 75.4 1,486 204 P10115715 auhydride 40.5 411 1,730 64.7 75.41,436 201 M61516 anhydride 26.5 40 1,730 64.7 75.4 1,480 202 Citraconicanhydridemh 30.4 40 1, 730 64. 7 75. 4 l, .86 204 Aoonitic acid 47. 6 2,640 42.4 61.9 1, 310 205 Diglycollic acid 30.2 501 2,640 42.4 61.9 1,310204 P11152115 anhydride"-.. 33.4 511 2,640 42.4 61.9 1,810 205 Maleicanhydride... 1. 22.2 511 2, 640 42.4 01.9 1,810 205 Aoonitic acid 39.350 2, 640 42.4 01.9 1,810 206 Citraconic anhydridenn 25.6 3,830 20.247.1 2,380 203 Diglycollic acid 22.8 60 3, 830 29. 2 47. l 2, 380 203Phthalic anhydridc. 25. 2 611 3,830 20.2 47.1 2,330 202 11215162511101166... 16.7 641 3, 830 2 47. l 2, 380 203 Aconitic acid 29. 6 0113,330 20.2 47.1 2,330 203 0102501115 anhydrida... 19.3 711 4,560 24.651.4 2,170 206 Phthalic anhydride 28.1 4,560 24.6 51.4 2,170 204 M21416nnhydride 13.5 711 4, 560 24.6 51.4 2,170 203 Citraconic anhydridd...21.0 70 4,360 24.6 51.4 2,170 205 Aconitic acid 32.7 70 4,560 24.0 51.42,170 205 Diglycollic acid 24.6 811 7,770 14.4 33.3 2, 920 212 .....do10.4 30 7, 770 14.4 33.3 2, 020 210 P11156115 211 111001116..." 21.1 307, 770 14.4 33.3 2, 020 203 M21616 anhydride 13.6 7, 770 14.4 38.3 2,020203 Aconitic acid 24.2 811 7, 770 14.4 38.3 2,920 205C1traconicanhydride. 15.7

TABLE 3 tion of the entire molecule, more difiiculty is involved inobtaining complete esterification. Estori- Time of r Ex. N0. of s 1 t 1fication Esteri Water 4 Even under the most carefully controlled conacid ester 0,153 15 fiCLLtlOIl out 55, d ditlons of oxypropylatlonlllVOlVlllg comparatlve- 7 J 1y low temperatures and long time ofreaction,

1 there are formed certain compounds whose com- #7-3 233 171 3/2 5.2 #Hm 3% None pos1t1on 1s st1ll obscure. Such slde react on #7-3 225 147 414None y products can contribute a substantial proportion 3,32 fg 00 ofthe final cogeneric reaction mixture. Various #7-3 231 2:4 4.1suggestions have been made as to the nature of J! 1 5 231g thesecompounds, such as being cychc polymers #744 240 185 2 4.0 of propyleneoxide, dehydration products with l" n the appearance of a vinyl radlcal,or isomers of 117-3 223 137 512 510116 50 propylene oxide or derivativesthereof, 1. e., of 23:2 3.53 an aldehyde, ketone, or allyl alcohol. Insome fi7-3 223 1%; .6 instances, an attempt to react the stoichiometricit; amount of a polycarboxy acid with the oxypropyl- 117-3 224 157 1% N00 ated derivative results in an excess of the car- 5 50 boxylatedreactant, for the reason that apparent- 7-3 220 183 1% 2 ly underconditions of reaction, less reactive iii; ,g; N223 hydroxyl radicalsare present than indicated by 37-3 223 the hydroxyl value. Under suchcircumstances, 221 6 /2 there is simply a residue of the carboxylicreactant which can be removed by filtration, or, if desired, theesterification procedure can be repeated, using an appropriately reducedratio of carbcxylic reactant.

Even the determination of the hydroxyl value by conventional procedureleaves much to be desired, due, either to the cogeneric materialspreviously referred to, or, for that matter, the presence of anyinorganic salts or propylene oxide. Obviously, this oxide should beeliminated.

The solvent employed, if any, can be removed from the finished ester bydistillation, and particularly vacuum distillation. The final productsor liquids are generally dark reddish amber to reddish amber in color,and show moderate visccsity. They can be bleached with bleaching clays,filtering chars, and the like. However, for the purpose ofdemulsification or the like, color is not a factor and decolorization isnot justified.

In the above instances, I have permitted the solvents to remain presentin the final reaction mass. In other instances, I have followed the sameprocedure, using decalin or a mixture of decalin or benzene in the samemanner and ultimately removed all the solvents by vacuum distillation.Appearances of the final products are much the same as the diols beforeesterification, and in some instances, were somewhat darker in color andhad a more reddish cast and perhaps somewhat more viscous.

PART 3 Previous reference has been made to the fact that diols(nitrogen-free compounds) such as polypropyleneglycol of approximately2,000 molecular weight, for example, have been esterified with dicarboxyacids and employed as demulsifying agents. The herein describedcompounds are different from such diols, although both, it is true, arehigh molecular weight dihydroxylated compounds. The instant compoundshave present a nitrogen atom which is basic in character. The basicityof such nitrogen atom may be decreased, due to the presence of the longalkylene oxide chain, but, in any event, it is quite possible that theorientation of the acid molecule, i. e., the acid ester, is influencedby the presence of the basic nitrogen atom. Stated another way, theultimate ester has at least two free carboxy radicals. It seemsreasonable to assume that the orientation of such molecules at anoil-water interface, for example, are affected by the presence of anitrogen atom having significant or definite basicity. Regardless ofwhat the difference may be, the fact still remains that the compounds ofthe kind herein described may be, and frequently are, or better on aquantitative basis than the simpler compound previously described, anddemulsify faster and give cleaner oil in many instances. The method ofmaking such comparative tests has been described in a booklet entitledTreating Oil Field Emulsions, used in the Vocational Training Course,Petroleum Industry Series, of the American Petroleum Institute.

It may be well to emphasize also the fact that oxypropylation does notproduce a single compound, but a cogeneric mixture. The factor involvedis the same as appears if one were oxypropylatin a monohydric alcohol ora glycol. Momentarily, one may consider the structure of a polypropyleneglycol, such as polypropylene glycol of 2,000 molecular weight.Propylene glycol has a primary alcohol radical and a secondary alcoholradical. In this sense the building unit which forms polypropyleneglycols is not symmetrical. Obviously, then, polypropylene glycols canbe obtained, at least theoretically, in which two secondary alcoholgroups are united, or a secondary alcohol group is united to a primaryalcohol group, etherization being involved, of course, in each instance.

Usually, no effort is made to differentiate between oxypropylationtaking place, for example, at the primary alcohol radical, or thesecondary alcohol radical. Actually, when such products are obtained,such as a high molal polypropylene glycol or the products obtained inthe manner herein described, one does not obtain a single derivativesuch as HO(RO)nH, in which n has one and only one value, for instance,14, 15 or 16, or the like. Rather, one obtains a cogeneric mixture ofclosely related or touching homologucs. These materials invariably havehigh molecular weights and cannot be separated from one another by anyknown procedure without decomposition. The properties of such mixturerepresent the contribution of the various individual members of themixture. On a statistical basis, of course, n can be appropriatelyspecified. For practical purposes, one need only consider theoxypropylation of a monohydric alcohol, because, in essence, this issubstantially the mechanism involved. Even in such instances where oneis concerned with a monohydric reactant, one cannot draw a singleformula and say that by following such procedure, one can readily obtainor or of such compound. However, in the case of at least monohydricinitial reactants, one can readily draw the formulas of a large numberof compounds which appear in some of the probable mixtures, or can beprepared as components and mixtures which are manufacturedconventionally.

Simply by way of illustration, reference is made to the co-pendingapplication of De Groote, Wirtel and Pettingill, Serial No. 109,791,filed August 11, 1949.

However, momentarily referring again to a monohydric initial reactant,it is obvious that if one selects any such simple hydroxylated compoundand subjects such compound to oxyalkylation, such as oxyethylation, oroxypropylation, it becomes obvious that one is really producing apolymer of the alkylene oxides, except for the terminal group. This isparticularly true where the amount of oxide added is comparativelylarge, for instance, 10, 20, 30, 40, or 50 units. If such compound issubjected to oxyethylation so as to introduce 30 units of ethyleneoxide, it is well known that one does not obtain a single constituent,which, for the sake of convenience, may be indicated as RO(C2H4O)30I-I.Indeed, one obtains a cogeneric mixture of closely related homologues,in which the formula may be shown as the following, RO(C2H4O) Til-I,wherein n, as far as the statistical average goes, is 30, but theindividual members present in significant amount may vary from instanceswhere n has a value of 25, and perhaps less, to a point where n mayrepresent 35 or more. Such mixture is, as stated, a cogeneric, closelyrelated series of touching homologous compounds. Considerableinvestigation has been made in regard to the distribution curves forlinear polymers. Attention is directed to the article entitledFundamental Principles of Condensation Polymerization, by Flory, whichappeared in Chemical Reviews, volume 39, No. 1, page 137.

Unfortunately, as has been pointed out by Flory, and otherinvestigators, there is no satisfactory method, based on eitherexperimental or mathematical examination, of indicating the exactproportion of the various members of touching homologous series whichappear in cogeneric condensation products of the kind described. Thismeans that from the practical standpoint, i. e., the ability to describehow to make the product under consideration, and how to repeat suchproduction time after time without difficulty, it is necessary to resortto some other method of description, or else consider the value of n, informulas such as those which have appeared previously and which appearin the claims, as representing both individual constituents in which nhas a single definite value, and also with the understanding that nrepresents the average statistical value, based on the assumption ofcompleteness of reaction.

This may be illustrated as follows: Assume that in any particularexample the molal ratio of the propylene oxide to cyclohexylamine orother specified primary amines is 30 to 1. Actually, one obtainsproducts in which n probably varies from to 20, perhaps even farther.The average Value, however, is 15, assuming, as previously stated, thatthe reaction is complete. The product described by the formula is bestdescribed also in terms of method of manufacture.

PART FOUR Previous reference has been made to oxyalkylating agents otherthan propylene oxide, such as ethylene oxide. Obviously, variants can beprepared which do not depart from what is said herein but do producemodifications. Cyclohexylamine or other suitable alicyclic amines can bereacted with ethylene oxide in modest amounts and then subjected tooxypropylation, provided that the resultant derivative is (a)water-insoluble; (b) kerosene-soluble, and (c) has present to 80alkylene oxide radicals. Needless to say, in order to havewater-insolubility and kerosenesolubility, the large majority must bepropylene oxide. Other variants suggest themselves, as, for example,replacing propylene oxide by butylene oxide.

More specifically, one mole of cyclohexylamine can be treated with 2, 4,or 6 moles of ethylene oxide and then treated with propylene oxide so asto produce a water-insoluble, kerosene-soluble oxyalkylatedcyclohexylamine in which there are present 15 to 80 propylene oxideradicals, as previously specified. Similarly, the propylene oxide can beadded first and then the ethylene oxide, or random oxyalkylation can beemployed, using a mixture of the two oxides. The compounds so obtainedare readily esterified in the same manner as described in Part 2,preceding. Incidentally, the diols described in Part 1 or themodifications described therein, can be treated with various reactants,such as glycide, epichlorohydrin, dimethyl sulfate, sulfuric acid,maleic anhydride, ethylene imine, etc. If treated with epichlorohydrinor monochloroacetic acid, the resultant product can be further reactedwith a tertiary amine such as pyridine, or the like, to give quaternaryammonium compounds. If treated with maleic anhydride to give a totalester, the resultant can be treated with sodium bisulfite to yield asulfosuccinate. Sulfo groups can be introduced also by means of asulfating agent, as previously suggested, or by treating thechloroacetic acid resultant with sodium sulfite.

I have found that if such hydroxylated compound or compounds are reactedfurther so as to produce entirely new derivatives, such new derivativeshave the properties of the original hydroxylated compound, insofar thatthey are effective and Valuable demulsifying agents for resolution ofwater-in-oil emulsions, as found in the petroleum industry, as breakinducers in doctor treatment of sour crude, etc.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent is:

1. Hydrophile synthetic products; said hydrophile synthetic productsbeing characterized by the following formula:

in which R is a hydrocarbon radical selected from the class consistingof cyclohexyl radicals, methylcyclohexyl radicals, and cyclohexylmethylradicals, and n and n are whole numbers, with the proviso that 11. plusn equals a sum varying from 15 to n" is a whole number not over 2 and Ris the radical of a polycarboxy acid selected from the group consistingof acyclic and isocyclic polycarboxy acids having not more than 8 carbonatoms and composed of carbon, hydrogen and oxygen of the formula:

coon

cooHm in which n" has its previous significance.

2. Hydrophile synthetic products; said hydrophile synthetic productsbeing characterized by the following formula:

in which n and n are whole numbers, with the proviso that 11. plus 11.equals a sum varying from 15 to 80; and R is the radical of a dicarboxyacid selected from the group consisting of acyclic and isocyclicdicarboxy acids having not more than 8 carbon atoms and composed ofcarbon, hydrogen and oxygen of the formula:

R COOH COOH his MELVIN X DE GROOTE.

mark Witnesses to mark:

W. C. ADAMS, I. S. DE Gnoorn.

wherein the dicarwherein the dicarwherein the dicar- No referencescited.

1. HYDROPHILE SYNTHETIC PRODUCTS; SAID HYDROPHILE SYNTHETIC PRODUCTSBEING CHARACTERIZED BY THE FOLLOWING FORMULA: